Use of ethanol for preserving steroid and indoleamine hormones in bird plasma

Goymann, Wolfgang; Schwabl, Ingrid; Trappschuh, Monika; Hau, Michaela

doi:10.1016/j.ygcen.2006.09.014

Cited by 46 publications

(27 citation statements)

References 15 publications

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“…After returning from the field samples were stored at −80°C. Testosterone concentration was determined by direct radioimmunoassay (RIA, following [56], for assay details see [16,17]). …”

Section: Methodsmentioning

confidence: 99%

Does a short-term increase in testosterone affect the intensity or persistence of territorial aggression? — An approach using an individual's hormonal reactive scope to study hormonal effects on behavior

Goymann

Villavicencio

Apfelbeck

2015

Physiology & Behavior

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“…After returning from the field samples were stored at −80°C. Testosterone concentration was determined by direct radioimmunoassay (RIA, following [56], for assay details see [16,17]). …”

Section: Methodsmentioning

confidence: 99%

Does a short-term increase in testosterone affect the intensity or persistence of territorial aggression? — An approach using an individual's hormonal reactive scope to study hormonal effects on behavior

Goymann

Villavicencio

Apfelbeck

2015

Physiology & Behavior

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“…We extracted CORT from plasma using dichloromethane within three weeks of dilution and measured CORT using a double-antibody 125 I radioimmunoassay (ImmuChem 07-107 103; MP Biomedicals, Orangeburg, NY) follow methods in Newman et al (2008). Ethanol dilution results in slight reductions in measured CORT (Goymann et al 2007) implying that comparison with studies using undiluted plasma should be conducted with caution. Nevertheless, because the ethanol storage period was of short and equal duration for all samples, our inferences are unaffected by sample preservation.…”

Section: Methodsmentioning

confidence: 99%

Storms drive altitudinal migration in a tropical bird

2010

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Although migration is a widespread and taxonomically diverse behaviour, the ecological factors shaping migratory behaviour are poorly understood. Like other montane taxa, many birds migrate along elevational gradients in the tropics. Forty years ago, Alexander Skutch postulated that severe storms could drive birds to migrate downhill. Here, we articulate a novel mechanism that could link storms to mortality risks via reductions in foraging time and provide, to our knowledge, the first tests of this hypothesis in the White-ruffed Manakin (Corapipo altera), a small partially migratory frugivore breeding on the Atlantic slope of Costa Rica. As predicted, variation in rainfall was associated with plasma corticosterone levels, fat stores, plasma metabolites and haematocrit. By collecting data at high and low elevation sites simultaneously, we also found that high-elevation residents were more adversely affected by storms than low elevation migrants. These results, together with striking temporal capture patterns of altitudinal migrants relative to storms, provide, to our knowledge, the first evidence that weather-related risks incurred by species requiring high food intake rates can explain altitudinal migrations of tropical animals. These findings resolve conflicting evidence for and against food limitation being important in the evolution of this behaviour, and highlight how endogenous and exogenous processes influence life-history trade-offs made by individuals in the wild. Because seasonal storms are a defining characteristic of most tropical ecosystems and rainfall patterns will probably change in ensuing decades, these results have important implications for understanding the ecology, evolution and conservation of tropical animals.

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“…The amount of plasma was measured with a Hamilton syringe and stored in 500 ml ethanol [32]. After returning from the field, samples were stored at 2808C.…”

Section: Methodsmentioning

confidence: 99%

Ignoring the challenge? Male black redstarts ( Phoenicurus ochruros ) do not increase testosterone levels during territorial conflicts but they do so in response to gonadotropin-releasing hormone

Apfelbeck

Goymann

2011

Proc. R. Soc. B.

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Competition elevates plasma testosterone in a wide variety of vertebrates, including humans. The 'challenge hypothesis' proposes that seasonal peaks in testosterone during breeding are caused by social challenges from other males. However, during experimentally induced male -male conflicts, testosterone increases only in a minority of songbird species tested so far. Why is this so? Comparative evidence suggests that species with a short breeding season may not elevate testosterone levels during territory defence. These species may even be limited in their physiological capability to increase testosterone levels, which can be tested by injecting birds with gonadotropin-releasing hormone (GnRH). We studied two populations of black redstarts that differ in breeding altitude, morphology and the length of their breeding season. Unexpectedly, males of neither population increased testosterone in response to a simulated territorial intrusion, but injections with GnRH resulted in a major elevation of testosterone. Thus, black redstarts would have been capable of mounting a testosterone response during the male -male challenge. Our data show, for the first time, that the absence of an androgen response to male -male challenges is not owing to physiological limitations to increase testosterone. Furthermore, in contrast to comparative evidence between species, populations of black redstarts with a long breeding season do not show the expected elevation in testosterone during male -male challenges.

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Use of ethanol for preserving steroid and indoleamine hormones in bird plasma

Cited by 46 publications

References 15 publications

Does a short-term increase in testosterone affect the intensity or persistence of territorial aggression? — An approach using an individual's hormonal reactive scope to study hormonal effects on behavior

Does a short-term increase in testosterone affect the intensity or persistence of territorial aggression? — An approach using an individual's hormonal reactive scope to study hormonal effects on behavior

Storms drive altitudinal migration in a tropical bird

Ignoring the challenge? Male black redstarts ( Phoenicurus ochruros ) do not increase testosterone levels during territorial conflicts but they do so in response to gonadotropin-releasing hormone

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